Re: RAIDframe: what if a disc fails during copyback

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> So you have drives A, B, and C.  A and B were live.  Let's say B is the
> one that failed.  You reconstructed onto C and have been running with A
> and C.
Yes.

> Now you have a new B (which in this case is the same hardware with new
> firmware) and want to put it back into service.  I'm not sure whether
> you want to put it into service in place of A or in place of C.  I'm
> going to assume C.
Yes.

> So, you'd pull C, replace it with B
No. I don't pull C. I re-add B (I have lots of empty slots).

> and initiate a reconstruct
No, a copyback (raidctl -B).

> which for RAID 1 means copying from A to B.
I don't know. I would expect it to copy from C to B.

> > 1. The replaced component fails
> 
> Is this B?  Or C?  Because it sounds to me as though C would be out of
> service at this point.
I mean B.

> > 2. The spare fails
> 
> Which is "the spare"?
C.

> Are you running with a hot spare?
Yes. I added C as a hot spare when B failed and started a reconstruction.

> I think a hot spare failing means nothing until/unless RAIDframe 
> tries to fall back on it.
Yes.

> > 3. The other, non-replaced component fails?
> 
> That would be A?
Yes.

> Based on the assumption that RAIDframe RAID 1 cannot handle more than 
> two drives (always true as far as I know, and the 9.0 raidctl(8) manpage 
> says it's still true as of 9.0)
The RAID-1 I'm speaking of does only have to components, but I did operate 
a RAIDframe RAID-1 on three components with 5.1 or something.